The aim of this study is to investigate the prevalence of antinucleosome antibody in systemic lupus erythematosus (SLE) and their association with disease activity and renal involvement. The study included 131 patients with SLE, 74 rheumatoid arthritis, 26 systemic sclerosis, and 50 healthy individuals. Antinucleosome antibody and anti-dsDNA antibody were measured by an enzyme-linked immunosorbent assay (ELISA). Antinuclear antibody was tested by immunofluorescence using HEp-2 cells. Out of 131 SLE patients, 72 (54.9%) were seropositive for antinucleosome antibody, which was significantly higher than only 3 of 74 (4%) patients with rheumatoid arthritis (X-2 = 52.82, P < 0.001); none of the patients with systemic sclerosis and 50 healthy individuals were seropositive. The sensitivity and specificity of antinucleosome antibodies in SLE were 83.6% and 70%, respectively. Fifty-one (38.9%) of SLE patients had renal involvement. Among these patients, the rate of antinucleosome positivity and anti-dsDNA were 74.5% and 78.4%, respectively. Antinucleosome antibodies were found to be 31.4% positive in SLE patients lacking anti-dsDNA antibody. Antinucleosome antibodies significantly correlated with disease activity (r = 0.428, P < 0.001) and anti-dsDNA (r = 0518, P < 0.001). The positivity of antinucleosome antibodies was significantly higher in patients with renal disease than the subjects without renal disease (X-2 = 12.89, P < 0.001). The results of our study have revealed that in SLE patients, antinucleosome antibody could be a useful parameter for the assessment of disease activity or renal involvement.